In our above-cited parent application, there is disclosed a dual chamber device for collecting and retaining two sequential samples of liquid, in particular fore-stream and mid-stream samples of urine from an individual. The dual chamber device is disclosed as having a generally cylindrical body with a funnel-shaped transverse inner wall that divides the body into upper and lower liquid receiving and containing chambers of approximately the same volume. A circular orifice in the transverse inner wall provides liquid communication between the two chambers. A stopper disposed in the lower chamber below the orifice is responsive to liquid filling the lower chamber to a predetermined level to float upwardly to close the orifice, whereby liquid introduced into the device stops entering the lower chamber and starts filling the upper chamber.
There is disclosed in a preferred embodiment of the dual chamber device a snap-on bottom cover that is formed having a central pedestal region beneath the orifice stopper and having a column in engagement with the stopper. The central pedestal is surrounded by a thin flexible spring-acting annular web. After liquid has been collected in both the lower and upper chambers, the device body is capped and the device is pushed downwardly onto the bottom cover pedestal that is resting on a firm surface. This downward pushing action on the bottom cover pedestal causes the bottom cover flexible web to flex upwardly so that the bottom cover column engaging the stopper pushes the orifice stopper upwardly into tight engagement with the orifice. The over-center locking of the flexed web locks the orifice stopper tightly into the orifice to prevent liquid leakage between the lower and upper chambers. A flexible gasket or seal mounted on the orifice stopper provides orifice sealing integrity.
In a variation dual chamber device a bottom cover pedestal extension is disclosed for enabling greater upward flexing of the bottom cover web to further assure proper over-center locking of the web and positively assure tight locking of the orifice stopper into the orifice, regardless of device orientation and/or any careless handling of the liquid containing device.
The present inventors have, however, just discovered that the above-described downward pushing of the dual chamber device onto the bottom cover pedestal and/or bottom cover pedestal extension to cause upward flexing of the bottom cover web and pushing of the orifice stopper tightly into the orifice causes a substantial air pressure increase in the lower chamber above the liquid level therein. This increased air pressure in the lower chamber could possibly be sufficient to cause liquid in the lower chamber to bleed past the stopper in spite of its being tightly locked into the orifice. Assuming possibly unclean fore-stream urine is contained in the lower chamber and clean mid-stream urine, which is desired for bacterial analysis, is contained in the upper chamber, any such bleeding of the fore-stream urine from the lower chamber past the orifice stopper could contaminate the mid-stream urine contained in the upper chamber, rendering its bacteriological analysis results inaccurate.
It is, therefore, a principal objective of the present invention to provide for the venting of air pressure from the lower chamber so as to guarantee that pressure-caused bleeding of liquid from the lower chamber into the upper chamber will not occur.